This attribute gives the appearance that the material is emitting incandescent light.
The emitted light color.
Texture map representing hot lava connected to Emission Color
Controls the amount of emitted light. It can create noise, especially if the source of indirect illumination is very small (e.g. light bulb geometry).
Increasing the number of Diffuse samples will help to reduce any noise in dark, indirectly lit areas of a scene when using emission.
Note that a Mesh light may work better in a situation where you need an object to emit light that casts realistic ray-traced shadows.